Caffeine increases gestation length on a commercial farm

In recent years, pressure for sow prolificacy has been applied to increase the number of pigs sold/sow/year. However, selection pressure on sow prolificacy and the resultant increase in litter sizes has adverse consequences, most notably increased stillbirths, lower birthweights, lower viability at birth and hence poor survival (Quiniou et al. 2002). Small scale studies have demonstrated that maternal caffeine supplementation on the day before parturition decreased stillbirths and increased piglet temperature at birth (Superchi et al. 2013, 2016). Recent data (B. A. Dearlove and W. H. E. J. van Wettere, unpubl. obs.) indicated that 3 days of caffeine supplementation (6 g/d) before parturition extended gestation length and increased piglet temperature shortly after birth. The aim of the current study was to determine the impact of caffeine supplementation of sow diets before parturition on gestation length and the incidence of stillbirths under commercial conditions. We hypothesised that caffeine would extend gestation length and reduce stillbirths.

Large White, Landrace, and Duroc sows (n = 348, parity 2.85 ± 0.10) were allocated to one of three treatment groups, Control (CTL, n = 122), 3 g/d caffeine (CAF3, n = 111) and 6 g/d caffeine (CAF6, n = 115). Treatment began at d 112 of gestation and continued until farrowing (CAF3: mean 3.74 ± 0.14 days treatment; CAF6: 3.91 ± 0.14 days treatment). Gestation length, total born, born alive and born dead, and piglet survival to processing (processing occurred within the first 24 h of life), d 4 and d 21 post partum were recorded. Statistical analysis was performed using a mixed general linear model (SPSS v24.0, IBM, Armonk, NY, USA) with treatment, breed, parity and whether the piglets were purebred or crossbred with total born as a covariate. Sow was treated as a random effect. Data from individual piglets were treated as repeated-measures on the sow in similar mixed linear models including the sow as a random factor. Data are presented as estimated means ± s.e. from mixed models. Total born (12.04 ± 0.39), born alive (10.92 ± 0.19) and stillbirths (0.93 ± 0.15) were unaffected by treatment. Treatment also did not affect piglet survival to processing (96.76 ± 0.86%), d 4 (91.50 ± 1.34%) and d 21 post partum (89.54 ± 1.88%). Gestation length was increased in the CAF6 group compared to the CTL group (CTL: 115.22 ± 0.21; CAF3: 115.76 ± 0.22; CAF6: 116.11 ± 0.23; P < 0.01) and tended to be increased in the CAF3 compared to the CTL group (P < 0.08). There was also a breed difference in gestation length with Landrace and Duroc sows having an extended gestation on the CAF6 treatment (Table 1).

Table 1.  Gestation length (d) for Large White, Landrace and Duroc sows receiving either no (CTL), 3 (CAF3) or 6 (CAF6) caffeine a day from d 112 of gestation until farrowing

The failure of caffeine to reduce stillbirths in this study may have been due to the intense supervision received under experimental conditions compared to commercial conditions (Superchi et al. 2013, 2016), suggesting that further studies should be conducted to confirm if caffeine supplementation does represent a commercial strategy to improve piglet survival. However, consistent with our previous data, gestation length was increased in response to caffeine supplementation. This is an important finding, as sows which farrow prematurely (<115 days) are likely to produce more stillborn and low viability piglets, with fewer of their piglets surviving to weaning (Vanderhaeghe et al. 2011). Maternal caffeine supplementation may, therefore, be a useful strategy for herds in which premature farrowing is a problem.